Tongs for forehearth skimmer blocks and the like



F. N. DAILEY Dec. 12, 1950 TONGS FOR FOREHEARTH SKIMMER BLOCKS AND THE LIKE Filed Sept. 11, 1947 HE m U flQa INVENTOR FRANCIS N. DAILEY ATTORNEYS Patented Dec. 12, 1950 TONGS FOR FQREHEARTH SHIMMER BLOCKS AND THE LIKE Francis N. Dailey, Rockville, Cnn., assignor to Hartford-Empire Company, Hartford, Conn., a corporation of Delaware Application September 11, 1947, Serial No. 773,338

2 Claims.

This invention relates to a device for use in removing and replacing refractory skimmer blocks of molten glass conducting forehearths or flow channels.

Molten glass forehearths customarily include a transversely extending refractory skimmer block which is supported, as on the side walls of the forehearth channel, so that the lower edge of the skimmer block is located at or just below the surface of the molten glass in the forehearth channel. Such a skimmer block may require removal and replacement while the forehearth is in operation either because the skimmer block has been worn by erosion of the glass or has broken or cracked in service or for other reasons. The skimmer block is located in a zone of high temperature and is too hot to be grasped and lifted by hand. Prior to the present invention, it has been customary to remove such 2. skimmer block by the use of pry bars and other available tools, manipulated by workmen. This not only is hazardous for the workmen but is a diflicult and tedious operation. Even with care, the hot skimmer blocks or a part thereof if it should be cracked or broken, may fall or slip away from a supporting bar or other tool. Also, in setting a new skimmer block in place in the forehearth, it is necessary first to effect preheating of the block, as to a temperature of 800' or 900 F. before the skimmer block is placed in its operative position. Otherwise the new skimmer block is likely to be broken by heat shock when it is first ekposed to the high temperature existing in the forehearth channel. Sometimes, in order to avoid handling a skimmer block preheated to such a high temperature, the skimmer block is propped on temporary supporting blocks above the location at which it is to be set and thereafter the supporting blocks are knocked out of their supporting positions gradually to lower the skimmer block toward and ultimately to its final position as it becomes preheated by heat from the forehearth.

A general object of the invention is to facilitate removal of a skimmer block from a fore hearth channel and its replacement by a new skimmer block and to do this without requiring manual handling of the block or exposure of a workman to the hazards incident to the prior practice.

A more specific object of the invention is to provide a tongs by which a hot skimmer block can be firmly, although releasably, gripped and moved by a hoist or other mechanical device under the control of a Workman, as for the removal of a hot skimmer block from a forehearth channel or the positioning of a new preheated skimmer block in the forehearth channel.

A further object of the invention is to provide a tongs of the character described which will afiord facilities for engaging a hot skimmer block so as to tend to maintain parts thereof against separation in the event the skimmer block is cracked.

A further object of the invention is to provide a tongs of the character described which is reliable in use, relatively simple construction and includes no clamping screws or threaded parts which are likely to be impaired or rendered inoperative by refractory dust or the heat to which the device will be subjected or to require adjustment by a wrench or the like in a hot or dangerous environment.

Other objects and advantages of the invention hereinafter will be pointed out or will become obvious from the followingdescription of a tongs embodying the present invention and a typical use thereof, such embodiment being shown in the accompanying drawings, in which:

Fig. 1 is a face view of a skimmer block with the tongs of the present invention engaged therewith at a time when the skimmer block has been lowered to its operative position in a molten glass forehearth channel which is shown in section, the view also showing in dot-and-dash lines the relative positions of the movable parts of the tongs after the latter has been operated to release the skimmer block and raised above it;

Fig. 2 is a relatively enlarged plan view of the tongs engaged with the skimmer block as shown in full lines in Fig. 1, the forehearth being omitted; and

Fig. 3 is a section through the tongs substantially along the ine 3-3 of Fig. 2, with the skimmer block omitted.

The novel tongs of the present invention comprises a rigid crossbar I made of steel or other suitable metal or material and of sufiicient length to ext nd a. short distance beyond each of the side edges of the upper part of a refractory skimmer block 2 when the crossbar is disposed above and parallel to the top of the skimmer block with the transverse median line of the crossbar approximately aligned with the vertical median line of the skimmer block. A. pair of depending tong arms 3 are mounted by horizontal pivot pins 4 on the crossbar i at equal distances from the transverse median line of the crossbar such that these arms will hang vertical beside the opposite side edges of a relatively wide upper portion 2a, of the skimmer block when the crossbar I is disposed above the skimmer block as above stated. The tong arms 3 are provided at their lower ends with rigid inturned block en'- gaging elements or tong fingers 5 which are then located in positions to extend into lateral notches or recesses 6 in the side edges of the upper portion of the skimmer block, these notches preferably being provided in such skimmer block just above the downwardly facing shoulders 1 provided on the skimmer block because of the relatively less width of its narrower lower portion 2b. The narrower portion 2b of the skimmer block is adapted to fit between the side walls 8 of a refractory forehearth channel 9 to a level just below the surface of a stream of molten glass It in that forehearth channel when the downwardly facing shoulders I rest upon the upper edges of the sides 8 of the forehearth channel, as shown in Fig. l.

The crossbar l is provided on its lower sunface with presser blocks or pads H which re.- spectively are located equ'i-distant from the transverse median line of the crossbar intermediate that transverse median line and the planes of the side edges of the upper part 2a of the skimmer block so as to bear'downwardly on the upper surface of the skimmer block when the tong fingers ii are engaged in the notches ii in the side edges of the skimmer block. These blocks or pads ii may be made of steel or any other suitable material which obviously may include a material that is sufficiently com ressible to assure firm contact with the uppersurface of the skimmer block without interfering with movement of the tong fingers 5 to their engaged positions in the notches 5 should the dimension of the parts involved vary slightiy from optimum or specified dimensions. As shown by Figs. 2 and 3, these blocks or pads H extend beyond opposite sides of the crossbar E so as to contact with the top surface of the skimmer block 2 through u the greater part of its width.

The crossbar i also carries depending abutments or stops 52 in positions to be located close to but outwardly of the side edges or the upper corner portions of the skimmer block when-the tong fingers are engaged in the slots 6 of the skimmer block and'the pads or blocks ii bear against its upper surface, as shown in Fig. 1. These abutments or stops'i2 maybe short metal angles l3 welded or otherwise rigidly secured to the lower side or" the crossbar I at appropriate places'along the length of the latter, these angle pieces being of sumcient length to extend short distances beyond opposite sides of the crossbar I as is clear from Figs. 2 and 3.. of the abutments or stops i2 is to limit relative longitudinal movements between the crossbar -l and the skimmer block 2 when the tong fingers 5 are engaged in the notches ii to only such movements as will not permit either tong finger to be accidentaily disengaged from its notch. V

The crossbar i is provided intermediate th pivot elements it with an upstanding rigid attaching lug or plate It. This has a hole it provided therein near its upper end and inter- ,ediate its side edges, with which a hook it at the lower end of the chain [7 of' a hoist (not shown) may be engaged. The hoist or any other suitable known mechanical lifting aid may of course be used to support and move the tongs for use of the latter as hereinafter will be described. Y

- The tong arms ,3 are provided with actuators The purpose in the form of rigid arms 18 which may be formed integral with the tong arms so as to extend upwardly above the crossbar l in planes which are inclined inwardly or toward each other. The actuating arms W are operable by a second crossbar I9 with which they are connected for limited sliding and oscillatory or swivelling movements. As shown, the arms 98 are provided near their upper ends with blocks 29 rigid therewith, as by being welded thereto, these blocks being provided with aligned bores 25 which are oversize in relation to the transverse dimensions of the second crossbar H9. The latter may be a length of round metal pipe or rod and the diameter of the bore 2| ineach of the blocks 26 is suiiiciently greater than the diameter of the round pipe or rod to permit suiiicient swivelling or oscillatory movements of the blocks 2!! relative to the bar E9 to permit them to slide along the latter when the actuating arms are to be operated to swing the tong arms between closed and open positions as shown by' full linesand dot-andedash lines, respectively, int-Fig. l,

The crossbar i9 is of greaterieng-th than the crossbar i so that it'has I rojectin end portions, indicated at idea, which may be grasped by workmen when it is desired manually to carry or move the tongs.

A pair of guard elements in the form of collars 22 may be provided .on thecrossbar 58 at places adjacent to but equi-olistant from it middle point.

In use to remove a skimmer block from the forehearth channel, the tongs may be lowers?! while the tong arms are open, as shown by the dot-and-dash lines in the upper part of Fig. l,

the hook of the hoist, ifone is employed, then 7 being engaged with the attaching lug or plate i i on the crossbar i At this time, the cross.- bar I?! will bear against lower portions of the walls of the bores 2| in the blocks 29, at least at the outer ends of such bores, as shown by the ,dot-andedash linesin Fig. 1 andthe blocks 26 will be located at positions spaced inwardly from stop pins 23 on the crossbar is, the tong arms 3 being in their outwardly swung positions. When the tongs have been moved until the crossbar I is positioned above the skimmer block 2 as shown by the full lines'in Fig. -l, the hook of the hoist is disengaged from the attaching lug i l and engaged with the portion of: the crossbar 19 between the collars 22. Now, when a lift is applied to the crossbar 19, the blocks 28 will slide outward on such bar against the stop ins 23 and the tong fingers 5 will enter the notches t in the side edges of the skimmer block. A further'upward pull on the crossbar .153 will lift the entire tongs mechanism with the tong fingers engaged in thenotches dso as to lift the skimmer block from the iorehearth channel. It will be observed that this skimmer block will then be compressed sufficiently between the tong fin.- gers 5 with relation to one another and between these tong fingers and the pads or blocks H to maintain the skimmer block in compression and thereby to prevent separation of it into anumber of parts should it be cracked. Also, such clam-ping of the skimmer block to the tongs will lowered to a suitable supporting surface (not shown), it is only necessary to detach the hook of the hoist chain from the upper crossbar 19, as for subsequent attachment to the apertured lug or plate M. The weight of the crossbar l9, bearing down on the blocks and the inclined arms l8, will cause the tong arms 3 to swing apart as the blocks slide inwardly on the crossbar [9 from the positions shown by full lines in Fig. 1 to the positions shown by dot-and-dash lines in the same view.

To install a new skimmer block in the desired position in a forehearth, as shown in Fig. l, the tong fingers may be engaged in the notches in the side edges of that skimmer block, which may be suitably preheated. The hook of the hoist chain may be engaged with the upper crossbar 19 for the installation and the skimmer block moved by the hoist and. under the control of a workman to the desired position. The tong fingers then may be disengaged from the skimmer in a manner which has been explained. Thus, the workman can control the movements of the mechanism required for removal and replacement of a skimmer block While remaining at a safe distance from hot refractory parts and the hot iorehearth environment.

The novel tongs of the invention is designed and intended for use to remove and replace hot skimmer blocks of molten glass conducting forehearths but is not limited thereto as it may be used to transport any other work piece or article which may be gripped and carried thereby. Nor do I wish to be limited to the details of the illustrative embodiment of the invention shown in the drawings and herein particularly described as many modifications of and changes therein will now be obvious or readily occur to those skilled in the art.

I claim:

1. A tongs, for a glass forehearth skimmer block or other workpiece, comprising a crossbar, a pair of tong arms pivotally suspended from the crossbar, workpiece engaging elements on the tong arms, a second crossbar, and means operatively connecting said second crossbar with said tong arms to cause the latter to be swung relative to each other in certain directions when the tongs is supported by the second crossbar and in the opposite directions when the tongs is supported by the first crossbar, said means comprising a pair of upturned actuating arms integral with said tong arms and extending above said first crossbar in planes inclined toward each other, and blocks carried by said actuating arms, said blocks having horizontally aligned bores loosely receiving said second crossbar, said bores being oversize in relation to the size of the second crossbar to permit limited sliding movements of the blocks on the second crossbar without binding of these parts.

2. A tongs comprising a crossbar, a pair of tong arms pivotally suspended from the crossbar, inturned tong fingers on said tong arms, upturned actuating arms rigid with said tong arms and extending above said crossbar in directions inclined toward each other, blocks rigid with said upturned actuating arms, said blocks having horizontally aligned bores, a second crossbar of smaller diameter than said bores, said second crossbar extending through and being loosely supported by the bores of said blocks, whereby said blocks may move longitudinally of the crossbar to limited extents on relative vertical movements between said two crossbars, stop elements on said second crossbar to limit the outward movements of said blocks on the second crossbar, and an apertured attaching lug fast to and upstanding from the middle portion of said first crossbar, said attaching lug and the adjacent portion of said second crossbar being adapted to be engaged alternatively by a hook of a hoist or the like.

FRANCIS N. DAILEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,618,568 Carlson Feb. 22, 1927 2,437,485 Sonnerschein Mar. 9, 1948 

